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Skowicki M, Tarvirdipour S, Kraus M, Schoenenberger CA, Palivan CG. Nanoassemblies designed for efficient nuclear targeting. Adv Drug Deliv Rev 2024; 211:115354. [PMID: 38857762 DOI: 10.1016/j.addr.2024.115354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 05/23/2024] [Accepted: 06/04/2024] [Indexed: 06/12/2024]
Abstract
One of the key aspects of coping efficiently with complex pathological conditions is delivering the desired therapeutic compounds with precision in both space and time. Therefore, the focus on nuclear-targeted delivery systems has emerged as a promising strategy with high potential, particularly in gene therapy and cancer treatment. Here, we explore the design of supramolecular nanoassemblies as vehicles to deliver specific compounds to the nucleus, with the special focus on polymer and peptide-based carriers that expose nuclear localization signals. Such nanoassemblies aim at maximizing the concentration of genetic and therapeutic agents within the nucleus, thereby optimizing treatment outcomes while minimizing off-target effects. A complex scenario of conditions, including cellular uptake, endosomal escape, and nuclear translocation, requires fine tuning of the nanocarriers' properties. First, we introduce the principles of nuclear import and the role of nuclear pore complexes that reveal strategies for targeting nanosystems to the nucleus. Then, we provide an overview of cargoes that rely on nuclear localization for optimal activity as their integrity and accumulation are crucial parameters to consider when designing a suitable delivery system. Considering that they are in their early stages of research, we present various cargo-loaded peptide- and polymer nanoassemblies that promote nuclear targeting, emphasizing their potential to enhance therapeutic response. Finally, we briefly discuss further advancements for more precise and effective nuclear delivery.
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Affiliation(s)
- Michal Skowicki
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 22, 4058 Basel, Switzerland; NCCR-Molecular Systems Engineering, BPR 1095, Mattenstrasse 24a, 4058 Basel, Switzerland
| | - Shabnam Tarvirdipour
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 22, 4058 Basel, Switzerland
| | - Manuel Kraus
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 22, 4058 Basel, Switzerland
| | - Cora-Ann Schoenenberger
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 22, 4058 Basel, Switzerland; NCCR-Molecular Systems Engineering, BPR 1095, Mattenstrasse 24a, 4058 Basel, Switzerland.
| | - Cornelia G Palivan
- Department of Chemistry, University of Basel, BPR 1096, Mattenstrasse 22, 4058 Basel, Switzerland; NCCR-Molecular Systems Engineering, BPR 1095, Mattenstrasse 24a, 4058 Basel, Switzerland.
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Ahmad B, Lerma-Reyes R, Mukherjee T, Nguyen HV, Weber AL, Schulze WX, Comer JR, Schrick K. Nuclear localization of HD-Zip IV transcription factor GLABRA2 is driven by Importin α. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.03.565550. [PMID: 37961624 PMCID: PMC10635128 DOI: 10.1101/2023.11.03.565550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
GLABRA2 (GL2), a class IV homeodomain leucine-zipper (HD-Zip IV) transcription factor (TF) from Arabidopsis , is a developmental regulator of specialized cell types in the epidermis. GL2 contains a putative monopartite nuclear localization sequence (NLS) partially overlapping with its homeodomain (HD). We demonstrate that NLS deletion or alanine substitution of its basic residues (KRKRKK) affects nuclear localization and results in a loss-of-function phenotype. Fusion of the predicted NLS (GTNKRKRKKYHRH) to the fluorescent protein EYFP is sufficient for its nuclear localization in roots and trichomes. The functional NLS is evolutionarily conserved in a distinct subset of HD-Zip IV members including PROTODERMAL FACTOR2 (PDF2). Despite partial overlap of the NLS with the HD, genetic dissection of the NLS from PDF2 indicates that nuclear localization and DNA binding are separable functions. Affinity purification of GL2 from plant tissues followed by mass spectrometry-based proteomics identified Importin α (IMPα) isoforms as potential GL2 interactors. NLS structural prediction and molecular docking studies with IMPα-3 revealed major interacting residues. Split-ubiquitin cytosolic yeast two-hybrid assays suggest interaction between GL2 and four IMPα isoforms from Arabidopsis. Direct interactions were verified in vitro by co-immunoprecipitation with recombinant proteins. IMPα triple mutants ( impα- 1,2,3 ) exhibit defects in EYFP:GL2 nuclear localization in trichomes but not in roots, consistent with tissue-specific and redundant functions of IMPα isoforms in Arabidopsis . Taken together, our findings provide mechanistic evidence for IMPα-dependent nuclear localization of GL2 and other HD-Zip IV TFs in plants. One sentence summary GLABRA2, a representative HD-Zip IV transcription factor from Arabidopsis , contains an evolutionarily conserved monopartite nuclear localization sequence that is recognized by Importin α for translocation to the nucleus, a process that is necessary for cell-type differentiation of the epidermis.
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Bhambid M, Dey V, Walunj S, Patankar S. Toxoplasma Gondii Importin α Shows Weak Auto-Inhibition. Protein J 2023:10.1007/s10930-023-10128-2. [PMID: 37284905 DOI: 10.1007/s10930-023-10128-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2023] [Indexed: 06/08/2023]
Abstract
Importin α is a nuclear transporter that binds to nuclear localization signals (NLSs), consisting of 7-20 positively charged amino acids found within cargo proteins. In addition to cargo binding, intramolecular interactions also occur within the importin α protein due to binding between the importin β-binding (IBB) domain and the NLS-binding sites, a phenomenon called auto-inhibition. The interactions causing auto-inhibition are driven by a stretch of basic residues, similar to an NLS, in the IBB domain. Consistent with this, importin α proteins that do not have some of these basic residues lack auto-inhibition; a naturally occurring example of such a protein is found in the apicomplexan parasite Plasmodium falciparum. In this report, we show that importin α from another apicomplexan parasite, Toxoplasma gondii, harbors basic residues (KKR) in the IBB domain and exhibits auto-inhibition. This protein has a long, unstructured hinge motif (between the IBB domain and the NLS-binding sites) that does not contribute to auto-inhibition. However, the IBB domain may have a higher propensity to form an α-helical structure, positioning the wild-type KKR motif in an orientation that results in weaker interactions with the NLS-binding site than a KRR mutant. We conclude that the importin α protein from T. gondii shows auto-inhibition, exhibiting a different phenotype from that of P. falciparum importin α. However, our data indicate that T. gondii importin α may have a low strength of auto-inhibition. We hypothesize that low levels of auto-inhibition may confer an advantage to these important human pathogens.
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Affiliation(s)
- Manasi Bhambid
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Vishakha Dey
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
- Indiana University School of Medicine, Indianapolis, USA
| | - Sujata Walunj
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
- IITB-Monash Research Academy, IIT Bombay, Mumbai, India
| | - Swati Patankar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India.
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Jibiki K, Kodama TS, Yasuhara N. Importin alpha family NAAT/IBB domain: Functions of a pleiotropic long chameleon sequence. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2023; 134:175-209. [PMID: 36858734 DOI: 10.1016/bs.apcsb.2022.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Nuclear transport is essential for eukaryotic cell survival and regulates the movement of functional molecules in and out of the nucleus via the nuclear pore. Transport is facilitated by protein-protein interactions between cargo and transport receptors, which contribute to the expression and regulation of downstream genetic information. This chapter focuses on the molecular basis of the multifunctional nature of the importin α family, the representative transport receptors that bring proteins into the nucleus. Importin α performs multiple functions during the nuclear transport cycle through interactions with multiple molecules by a single domain called the IBB domain. This domain is a long chameleon sequence, which can change its conformation and binding mode depending on the interaction partners. By considering the evolutionarily conserved biochemical/physicochemical propensities of the amino acids constituting the functional complex interfaces, together with their structural properties, the mechanisms of switching between multiple complexes formed via IBB and the regulation of downstream functions are examined in detail. The mechanism of regulation by IBB indicates that the time has come for a paradigm shift in the way we view the molecular mechanisms by which proteins regulate downstream functions through their interactions with other molecules.
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Affiliation(s)
- Kazuya Jibiki
- Graduate School of Integrated Basic Sciences, Nihon University, Setagaya-ku, Tokyo, Japan
| | - Takashi S Kodama
- Laboratory of Molecular Biophysics, Institute for Protein Research, Osaka University, Osaka, Japan.
| | - Noriko Yasuhara
- Graduate School of Integrated Basic Sciences, Nihon University, Setagaya-ku, Tokyo, Japan.
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Jin L, Zhang G, Yang G, Dong J. Identification of the Karyopherin Superfamily in Maize and Its Functional Cues in Plant Development. Int J Mol Sci 2022; 23:ijms232214103. [PMID: 36430578 PMCID: PMC9699179 DOI: 10.3390/ijms232214103] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/06/2022] [Accepted: 11/13/2022] [Indexed: 11/18/2022] Open
Abstract
Appropriate nucleo-cytoplasmic partitioning of proteins is a vital regulatory mechanism in phytohormone signaling and plant development. However, how this is achieved remains incompletely understood. The Karyopherin (KAP) superfamily is critical for separating the biological processes in the nucleus from those in the cytoplasm. The KAP superfamily is divided into Importin α (IMPα) and Importin β (IMPβ) families and includes the core components in mediating nucleocytoplasmic transport. Recent reports suggest the KAPs play crucial regulatory roles in Arabidopsis development and stress response by regulating the nucleo-cytoplasmic transport of members in hormone signaling. However, the KAP members and their associated molecular mechanisms are still poorly understood in maize. Therefore, we first identified seven IMPα and twenty-seven IMPβ genes in the maize genome and described their evolution traits and the recognition rules for substrates with nuclear localization signals (NLSs) or nuclear export signals (NESs) in plants. Next, we searched for the protein interaction partners of the ZmKAPs and selected the ones with Arabidopsis orthologs functioning in auxin biosynthesis, transport, and signaling to predict their potential function. Finally, we found that several ZmKAPs share similar expression patterns with their interacting proteins, implying their function in root development. Overall, this article focuses on the Karyopherin superfamily in maize and starts with this entry point by systematically comprehending the KAP-mediated nucleo-cytoplasmic transport process in plants, and then predicts the function of the ZmKAPs during maize development, with a perspective on a closely associated regulatory mechanism between the nucleo-cytoplasmic transport and the phytohormone network.
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Affiliation(s)
- Lu Jin
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Guobin Zhang
- College of Agronomy, Shandong Agricultural University, Taian 271018, China
| | - Guixiao Yang
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
| | - Jiaqiang Dong
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
- Correspondence:
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